I am currently in chapter 2, before setting up the meeting with leuvardeen and triss at the inn. I was hunting in the swamp and killed a varg, and a female wyvern. I got a quest trigger for both but i could only hold one trophy. If i leave on on the ground a return later will it still be there?

Quest trophies are an exception and they stay on the ground even if you leave the area. It happened to me in another chapter; I was able to come back and retrieve the second trophy.